Heng Long has released a new set of electronics for their tanks, the TK-RX18 (labelled as Multi-function Unit). So far, the only tank with the TK-RX18 is the Stug III, but the Pz IV and Jagdpanther will likely be available with it shortly. This new board was released in order to provide IR battling capability, and any IR capable tanks will come with it. It's possible that at some point Heng Long may release airsoft tanks with the TK-RX18 board (instead of the RX13/RX14 boards), as the rest of the functions remain the same. This would be a good thing, as the TK-RX18 should be a more reliable board.GENERAL NOTESCONNECTING

You can use a HBU as a sensor if desired, but with some caveats as indicated below. This is the pinout. Note that it doesn't have any LEDs, so it can be hard to tell when you're hit. You could run LEDs separately and arrange them in the cupola or around the tank. Two LEDs in series with a 100 ohm resistor form a string, make two strings. The connect the strings in parallel to LED+ and LED- on the DBC board.
The IR LED can be used as is, with minor caveats indicated below.